Same thing happens to me only explanation I have for it is that the launcher is opening two versions of itself when you launch the game, I have not found found a way to fix this yet except for closing the launchers task in task manager after I launch the game though this only fixed the problem for that session. I don't know if yours does this as well but after I launch the game Minecraft itself under java(TM) platform SE binary uses 60 percent of my CPU until my computer auto stops it making it not respond and then the game doesn't load until I end the launchers task.
Owen Joy
Same thing happens to me only explanation I have for it is that the launcher is opening two versions of itself when you launch the game, I have not found found a way to fix this yet except for closing the launchers task in task manager after I launch the game though this only fixed the problem for that session. I don't know if yours does this as well but after I launch the game Minecraft itself under java(TM) platform SE binary uses 60 percent of my CPU until my computer auto stops it making it not respond and then the game doesn't load until I end the launchers task.